Roger , i have used this circuit many times . and was going to do an diary on it.
it is essentially like yours but a little more clear.
minus the bells and whistles.
the Fet is pulsed with pwm to vary the current into the battery , it is very useful when the alternator voltage is greater than the battery voltage , and assumming the blades cant overpower the alt , it should work very well, because it will let the blades speed up to their designed TSR , and hopefully stay there ,and as the wind increases the pwm can be turned up
i just have to marry this with the boost converter and the system will be complete.
lots of work to do still, it should be interesting
note : for clarity i've left out the pwm driving the fet and the monitoring system which isnt yet complete.
